This program is a collaborative study of cellular and molecular aspects of the transport of respiratory gases between the environment and the subcellular site of metabolism. It is divided into eleven projects and two core facilities; (1) three on cellular function of the lungs; (2) two on rapid exchanges within the blood; (3) six on oxygen metabolism and exchange in the periphery; (4) two core units, a mass spectrometer facility and a cell analytical facility. The projects dealing with lung cellular function now have a preparation of Type II cells available and will investigate their biochemistry. The relation between the Na-K ATPase inhibition and prostaglandin production will be followed up. Broad studies on the nervous inhibition in control of contraction of airways smooth muscle will continue. The studies on blood gas transport (2) will include further exploration of the kinetics of CO2 exchanges in the lungs, blood and tissues, and ionic exchanges of red blood cells. The investigation of tissue metabolism activity (3) will include a comparison in the brain of local blood flow with local mitochondrial respiratory measurements of average tissue PO2 wit 1802-indicator dilution and CO shifts between hemoglobin and myoglobin, measurements of the stimulation of the carotid body and contraction of smooth muscle by decreased arterial PO2 and measurements of intracellular pH and H ion exchanges. The mass spectrometer core will expand the application of stable isotope measurements to organ and to subcellular physiology, taking advantage of the new instrument's ability to measure PCO. The research activity of this program are closely coordinated with the training activities of the Respiratory Physiology Group of the Department of Physiology.